TreeViewNodeCancelEventArgs.Cancel Property
Gets or sets a value indicating whether the action that raised the event should be canceled.
Namespace: DevExpress.Web
Assembly: DevExpress.Web.v19.1.dll
Declaration
Property Value
Type | Description |
---|---|
Boolean | true if the action that raised the event should be canceled; otherwise, false. |
Remarks
The TreeViewNodeCancelEventArgs object is passed to the events that fire before specific actions. The Cancel property of this object enables you to cancel the action which is about to be performed. Set this property to true to cancel the action that raised the event. This can be used if you want to prohibit performing the corresponding action with respect to specific conditions.
Example
The sample code below represents an ASPxTreeView.ExpandedChanging event handler. The event handler prevents collapsing nodes if it has selected children in any generation.
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-prevent-parent-node-collapsing-e2439
using DevExpress.Web.ASPxTreeView;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void ASPxTreeView1_ExpandedChanging(object source, DevExpress.Web.ASPxTreeView.TreeViewNodeCancelEventArgs e) {
if ((e.Node.Expanded) && (ASPxTreeView1.SelectedNode != null)) {
TreeViewNode node = ASPxTreeView1.SelectedNode.Parent;
while (node != null) {
if (e.Node == node) {
e.Cancel = true;
break;
}
node = node.Parent;
}
}
}
}